Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
An update: I found that by setting the debug clock frequency lower (1.8 MHz, down from 4.0 MHz) I stopped getting the errors. Maybe it was primarily a signal integrity issue on my debug cable?